dredged up from the Gulf of Manaar. 139 



cate with very short conical shaft, 6 by 3-1800ths, head 50- 

 1800ths in diameter (PI. VII. fig. 43, a, b) ; 2, acerate, smooth, 

 fusiform, curved, 27 by l-1800ths (fig. 43, c) ; 3, acerate 

 tiesh-spicule, smooth, fusiform, curved, inflated in the centre, 

 4-l800ths long (fig. 43, d, e) ■ 4, stellate flesh-spicule 4-6- 

 rayed, rays microspined, 3-6000ths (fig. 43, d, e) . The large 

 trifurcate spicule is parquetted in amongst the rest so as to 

 form a smooth even surface over an areolar structure, whose 

 thickness varies with the subjacent depressions of the Melo- 

 besian nodule over which the sponge is growing. Size about 

 one third of an inch in horizontal diameter. 



Hob. Marine. On hard objects. 



Log. Gulf of Manaar. 



Obs. Dwarfed as this variety is, one can see by its spicula- 

 tion, although modified by its habitat on the surface of the 

 Melobesian nodule, that it belongs to the Stellettina. The 

 trifurcate head, although necessarily with an extremely short 

 shaft, indeed hardly more than a short cone (fig. 43, b), and 

 the acerate spicule no. 2, are equivalent to the zone- and 

 body-spicule in Oeodia respectively ; while the central infla- 

 tion of the acerate flesh-spicule, although not microspined, 

 and the tendency in the stellate to assume a spinispirulate form, 

 ally it to the Tethea muricata of Bowerbank, the synonymy 

 of which I have already published ( l Annals,' 1878, vol. ii. 

 p. 174) ; but I find that, in this article, I have omitted to 

 mention that my dear old friend, Dr. J. E. Gray, in a note to 

 me, dated 3rd January, 1871, foreshadowed what I have 

 therein chiefly stated, viz. that " Bowerbank's figures of the 

 spicules of his Tethea muricata (B. S. vol. i. figs. 304, 305) 

 are probably those of Tisiphonia, Wyvillethomsonia and Dor- 

 villia respectively," which is now proved to be the case by 

 Dr. Bowerbank's own words and his illustrated description of 

 Tethea muricata (Proc. Zool. Soc. 1872, p. 115, pi. v. 

 figs. 1-6). 



The first mention of the name Tisiphonia for a sponge occurs 

 in Sir Wyville Thomson's paper on Holtenia Carpenteri (Phil. 

 Trans, vol. 159, p. 712), read before the Koyal Society on 

 the " 17th June, 1869," where, without more than the letters 

 "n. g." after it, he gives it as one of the genera illustrating 

 his "suborder Leptophlea." Subsequently we have the 

 name " Wyvillethomsonia " proposed as a generic appella- 

 tion for the same species by Dr. P. Wright in January 1870 j 

 and then comes Schmidt's of " Stelletta" in the month of 

 May following, ending with that of " Dorvillia " by Mr. 

 Saville Kent in Dec. 1870. 



Now it is evident that no one but Dr. Gray had seen that 



